In a study that provided a first-generation standardization of automated language environment estimates, validated these estimates against standard language assessments, it was found that the "word gap" between high-income and low-income groups was about 4 million by the time the children turned 4, not 30 million by age 3. Child vocalization frequency and turn-taking increased with age, whereas adult word counts were age independent after early infancy.
Lower socioeconomic status (SES) children produced fewer vocalizations, engaged in fewer adult–child interactions, and were exposed to fewer daily adult words compared with their higher socioeconomic status peers, but within-group variability was high. The results offer new insight into the landscape of the early language environment, with clinical implications for identification of children at-risk for impoverished language environments.
Gilkerson, J., Richards, J. A., Warren, S. F., Montgomery, J. K., Greenwood, C. R., Oller, D. K., Hansen, J. H. L., & Paul, T. D. (2017). Mapping the early language environment using all-day recordings and automated analysis. American Journal of Speech-Language Pathology, 26, 248-265. http://dx.doi.org/10.1044/2016_AJSLP-15-0169